Process of polymerizing isobutene in presence of titanium tetrahalide and a trihaloacetic acid



United States Patent ()fiiice 3,355,651 Patented Dec. 5, 1967 3,356,661PROCESS OF POLYMERIZING ISOBUTENE IN PRESENCE OF TITANIUM TETRAHALEDEAND A TRIHALOA-CETIC ACID Lester E. Coleman, Cleveland, Ohio, assignorto The Lubrizol Corporation, Wicklitie, Ohio, a corporation of Ohio NoDrawing. Continuation of application Ser. No. 255,205, Jan. 31, 1963.This application Nov. 28, 1966, Ser. No. 597,478

11 Claims. (Cl. 260-853) This application is a continuation ofapplication Serial No. 225,205, filed Jan. 31, 1963, and now abandoned.

This invention relates to an improved method for the production ofpolymerization products of isobutene and mixtures of isobutene and otherolefins and di-olefins.

It is well known that low molecular weight olefins such as ethylene,propylene, and isobutene are polymerized by catalysts of theFriedel-Crafts type, such as aluminum halides, ferric halides, zinchalides, boron halides, tin halides, mercuric halides, and titaniumhalides. The molecular weight of the polymer which results is greaterthe lower the polymerization temperature and the purer the reactants.For example, liquid isobutene may be polymerized at 1 12 F. using borontrifluoride as the catalyst to give a polymer having an averagemolecular weight of about 70,000. At 153 F. the products obtained havemolecular weights in the range of 150,000 to 200,000 or more. If,however, the isobutene is contaminated with other unsaturatedhydrocarbons, such as the n-butenes, the molecular weight of the polymerprepared at 153 F. is only 10,000 to 15,000.

Another catalyst which may be used to effect the polymerization ofolefins, such as isobutene, is a mixture of a titanium halide and aco-catalyst such as acetic acid, trichloroacetic acid, or sulfuric acid.The procedure consists of adding the co-catalyst, e.g., trichloroaceticacid, to a mixture of monomer, solvent and titanium halide. The reversemethod, in which the titanium halide is added to a mixture of monomer,solvent, and co-catalyst has also been used. In both methods, thetitanium halide and the cocatalyst come into contact with each other toform the catalyst in the presence of the olefin. Polymers prepared byeither method within the temperature range of to 60 F. have relativelylow molecular weights which seldom exceed 20,000 or 30,000.

Other catalysts which may be used to effect the polymerization of lowmolecular weight olefins are the double salts formed by the reaction ofa Friedel-Crafts halide such as titanium tetrachloride with acetic acidaccompanied by the evolution of hydrogen chloride. Polymers prepared byutilizing these double salts at temperatures in the vicinity of 60 F.are found to have average molecular weights up to about 5,000.

In order to prepare high molecular weight polymers, for example, 150,000and higher, by any of the procedures known in the art it is necessary toeffect the polymerization at temperatures below l00 F. In addition tothe added cooling expense, these methods suffer the disadvantage also ofdifiicult temperature control. Since the molecular weight of the polymeris dependent upon the temperature of the polymerization, a fluctuatingreaction temperature results in a mixture of polymers having a widerange of molecular weights.

Accordingly, it is an object of this invention to provide an eflicientprocess for the production of high molecular weight polymers.

It is also an object of this invention to provide a process for thepolymerization of olefins at a constant tempera ture.

It is a further object of this invention to provide a process wherebyhigh molecular weight polymers are obtained without resort to relativelylow polymerization temperatures.

It is a further object of this invention to provide a process for thepreparation of high molecular weight interpolymers from mixtures ofolefins.

These and other objects are obtained in accordance with this inventionby providing a process of polymerizing an olefin comprising the steps ofpreparing a catalyst by mixing a titanium halide with from about 0.1 toabout 10 molar proportions of a trihaloacetic acid and contacting saidcatalyst with an olefin selected from the class consisting of isobuteneand mixtures of isobutene and conjugated dienes to effectpolymerization.

The polymerization may be carried out over a wide range of temperatures.Ordinarily, a temperature below F. is chosen. When polymers havingmolecular weights in the range of 50,000 to 300,000 are desired, atemperature below about -10 is preferred. The lower the reactiontemperature, the higher the molecular weight of the polymer. Inasmuch asthe reaction is exothermic, external cooling may be required to maintainthe reaction temperature within the desired range.

Only a very small amount of the catalyst is needed to bring about thedesired polymerization. The amount of titanium halide present in thecatalytic mixture may be as low as 0.01 by weight based on the amount ofmonomer present. The preferred amount is in the neighborhood of 0.5-1.5although greater amounts may be used but appear to ofiFer littleadditional benefit.

The olefins useful as monomers in the process of this invention includeisobutene which may be of a commercial grade such as is obtained frompetroleum refinery streams containing minor amounts of C and Chydrocarbons. Mixtures of isobutene and conjugated dienes also areuseful monomers. Examples of the conjugated dienes which may be used arebutadiene, hexadiene, pentadiene, cyclohexadiene, cyclopentadiene,piperylene, isoprene, chloroprene, styrene, and a-methyl styrene. Therelative proportion of isobutene to conjugated diene may vary from about1:1 to about 99:1. For reasons of oilsolubility and stability, a weightratio in the range of 4:1 to 50:1 is gene-rally preferred. Specificexamples of such mixtures include the mixture of 98% (by weight) ofisobutene and 2% of piperylene; mixture of 98% of isobutene and 2% ofhexadiene; mixture of 98% of isobutene and 2% of cyclohexadiene; mixtureof 95% of isobutene ano 5% of piperylene; mixture of 95 of isobutene and5% of isoprene; mixture of of isobutene and 15% of piperylene; mixtureof 80% of isobutene and 20% of piperylene; mixture of 75% of isobuteneand 25% of chloroprene; mixture of 50% of isobutene and 50% ofpiperylene; mixture of 50% of isobutene and 50% of isoprene; mixture of98% of isobutene, 1% of isoprene and 1% of piperylene; mixture of ofisobutene, 3% of piperylene and 2% of chloroprene; and the mixture of95% of isobutene, 3% of piperylene, and 2% of isoprene. The relativeproportion of isobutene to diolefin is selected according to the desiredproperties of the finished prodnot.

The polymerization of isobutene containing various amounts of l-buteneand Z-butene likewise can be carried out by the process of thisinvention. Examples of such mixtures include the mixture of 80% ofisobutene and 20% of cis-2-butene; 80% of isobutene and 20% of trans-2-butene; 60% of isobutene and 40% of l-butene; 60% of isobutene and 40%of cis-2-butene; 60% of isobutene and 40% of a commercial mixture ofisomeric butenes.

The titanium halides useful in the preparation of the catalyst includetitanium tetrafluoride titanium tetrachloride, and titaniumtetrabromide. The trihaloacetic acids which are useful to prepare thecatalyst complex include trifluoroacetic acid, trichloroacetic acid, andtribromoacetic acid. Any combination may be used but for reasons ofconvenience, economy and reactivity, the titaniumtetrachloride-trichloroacetic acid mixture is preferred.

As stated previously, the particular feature of the process of thisinvention involves the step of separately preparing the catalyst complexand subsequently contacting the olefin with this preformed catalyst. Thecatalyst is pre pared by merely mixing the titanium halide and thetrihaloacetic acid. Although the catalyst mixture prepared from titaniumhalide and trihaloacetic acid in a molar ratio ranging from about 10:1to about 1:10 may be used satisfactorily, thepreferred range is fromabout 4:1 to 1:4 and especially from about 1:1 to about 2: 1.

A preferred method of preparing the catalyst is to mix the titaniumhalide and the trihaloacetic acid in an inert solvent such as carbontetrachloride, chloroform, trichloroethylene, chlorobenzene, pentane,hexane, heptane, cyclohexane, benzene, or toluene. The formation of thecatalyst is conveniently carried out at room temperature and no hydgogenhalide is evolved even if the solution is warmed to 1 F.

Halogen free acetic acids are not useful as co-catalysts in the processof this invention. The reaction of a titanium halide with acetic aciditself results in the loss of hydrogen halide and formation of a doublesalt as describedpreviously.

The solvent may be removed after the catalyst of the present inventionis formed so that the catalyst can be contacted with the olefin in theabsence of any solvent if so desired. Ordinarily, however, the catalystis prepared as a 5% to solution in any of the given solvents and isadded slowly to the olefin monomer. This procedure is. generallypreferred since it results in improved temperature control and polymershaving more uniform molecular weights.

T o carry outthe polymerization step, the olefinic reactant is usuallydissolved in a solvent such as carbon tetrachloride, chloroform,pentane, hexane, or heptane and the solution is brought into contactwith the catalyst. In most cases it is less preferable to carry out thepolymerization in the absence of a solvent because of processdifiiculties associated with temperature control and the handling ofviscous polymerized products. The monomer-solvent weight ratio may varyfrom 1:1 to 1:10 and the generally preferred ratio is 1:2.

After the polymerization is completed the titanium halide-trihaloaceticacid complex is removed by any of several methods. Addition of analcohol such as methanol, ethanol, or isopropanol to the reactionmixture precipitates the polymer product from the reaction mixture.Contacting the reaction mixture with ammonia is also an effective methodto remove the catalyst in the form of a solid complex which can beseparated by filtration. Still another method which is commerciallyattractive is to filter the reaction mixture through Fullers earth orsome other alkaline solid substance capable of retaining the catalyst byforming an insoluble complex.

The character of the product depends to a considerable extent on theparticular olefin or olefin mixture polymerized, on the purity of theoriginal reactants, and on the temperature of the reaction mixture. Asmentioned previously an important embodiment of the process of thisinvention involves the separate step of preparing the catalyst. Thus thecatalyst may be added to the reaction mixture at a rate which will notcause the reaction mixture to undergo sudden or substantial temperaturevariations. Since the molecular weight of a particular polymer is dcpendent upon the temperature of the polymerization reaction, a narrowtemperature range is desired if the average molecular weight of thepolymer is to represent a mixture of polymers having a narrow range ofmolecular Weights.

Another significant advantage of the process of this invention is thefact that olefins such as isobutene may be polymerized in the presenceof substances such as butenes which normally act as poisons. There aremany reports in the art which discuss the poisoning effect of thenbutenes when attempts are made to polymerize olefins containing varyingamounts of the n-butenes. Specifically, l-butene and 2-butene arereported to substantially reduce the molecular weight of a polymerprepared from isobutene contaminated with one of these materials.

However, mixtures of isobutene and trans-Z-butene have been readilypolymerized by the process of this invention since trans-Z-butenebehaves as a diluent rather than as a poison in this process. Thus, forexample, the use of 40% isobutene and 60% trans-Z-butene givesessentially the same molecular weight and isobutene conversion asobtained with pure isobutene. It is therefore unnecessary in mostinstances to undergo the expense of removing the trans-Z-butene whichmay be present in a commercial isobutene fraction.

The following examples are of this invention:

illustrative of the process Example 1 A mixture of grams (1.8 moles) ofisobutene and 200 grams of n-heptane is cooled to -10 F. The catalystwhich is prepared as a 10% solution in carbon tetrachloride bydissolving 1 gram of titanium tetrachloride and 0.114 gram oftrichl-oroacetic acid in 13.9 grams of carbon tetrachloride is addeddropwise to the cooled isobutene solution over a period of 1% hours. Thereaction temperature is maintained within the range of 10" F. to 6 F.throughout the addition by external cooling. The catalyst is thendestroyed by adding 400 ml. of methanol with stirring for /2 hour. Theupper methanol layer is de-. canted and the residue is dissolved in 250ml. of refluxing benzene. The clear solution is poured into 400 ml. ofmethanol to precipitatethe polymer. Methanol and benzene are removed bydecantation and the polymer is dried by heating at 250 F. for 18 hours.Polyisobutene prepared in this manneris a clear, colorless solid havinga molecular weight of 177x10 Example 2 A mixture of 100 grams (1.8moles) of isobutene and 200 grams of n-heptane is cooled to 25 F. Thecatalyst which is prepared as a 10% solution in carbon tetrachloride bydissolving 1 gram (0.0052 mole) of titanium tetrachloride and 0.43 gram(0.0026 mole) of trichloroacetic acid in 12.87 grams of carbontetrachloride is added dropwise to the cooled isobutene solution over aperiod of 45 minutes. The reaction temperature is maintained constant at25 F. throughout the reaction. After stirring the mixture an additional15 minutes, the catalyst is destroyed by adding 457 grams of methanol.The product which is recovered as the precipitate is dissolved inbenzene, reprecipitated in methanol and dried'by heating. Polyisobuteneprepared in this manner has a molecular weight of 260 10 Example 3 To300 grams (5.4 moles) of isobutene there is added a solution containing0.195 gram (0.001 mole) of titanium tetrachloride and 0.054 gram(0.00033 mole) of trichloroacetic acid in 1.7 grams of n-heptane over aperiod of 2 minutes while maintaining the reaction temperature at 29 F.The reaction mixture is maintained at this temperature and stirred for atotal of one hour. The catalyst is then destroyed by the addition ofmethanol which also precipitates the polymer. The precipitate, isdissolved in benzene and the clear solution is poured into 500 ml. ofmethanol. The precipitate is then dried by heating. Polyisobuteneprepared in this manner has a molecular weight of 181 x 10 Example 4 Thecatalyst is prepared by dissolving 0.19 gram (0.001 mole) oftitanium-tetrachloride and 0.08 gram (0.0005 mole) of trichloroaceticacid in 4.73 grams of n-heptane at 75 F. The catalyst is then added dropwise to 300 grams (5.4 moles) of isobutene over a period of 5 minutes.The reaction temperature is maintained at 25 throughout the addition andfor a total reaction time of 1 hour. The catalyst is then de-activated'by the addition of 10 ml. of methanol and the mixture is poured into1500 ml. of methanol to precipitate the polymer. The polymer isdissolved in hot benzene, reprecipitated with methanol, and dried byheating. The polyisobutene prepared in this manner has a molecularweight of 316x10 Example 5 A mixture of 100 grams (1.8 moles) ofisobutene and 200 grams of n-heptane is cooled to 25 F. To this mixturethere is added 7.5 grams of a solution containing the catalyst preparedby dissolving 1 gram (0.006 mole) of titanium tetrachloride and 0.43gram (0.0026 mole) of trichloroacetic acid in 13.57 grams of carbontetrachloride. The mixture is stirred for 2 hours while maintaining thereaction temperature below F., preferably between 20 and 25 F. Thereaction is concluded by adding 400 mls. of methanol with stirring. Themethanol is decanted and the precipitate dissolved in warm benzene byrefluxing. The benzene solution is poured into methanol to reprecipitatethe polymer. After removing the methanol benzene mixture, the polymer isdried by heating. The polyiso'outene prepared in this manner has amolecular weight of 216x10 Example 6 The procedure of Example 5 isrepeated with the exception that the mixture is stirred for 6 hoursrather than 2 hours. The polyisobutene prepared in this manner has amolecular weight of 128x10 Example 7 temperature is maintained between 0and F.

throughout the addition and for an additional minutes whereupon thecatalyst is removed by adding 400 ml. of methanol with stirring. Theproduct which is recovered as the precipitate is dissolved in benzene,re-precipitated in methanol, and dried by heating. Polyisobuteneprepared in this manner has a molecular weight of 135 X 10 Example 8 Amixture of 100 grams (1.8 moles) of isobutene and 200 grams of n-heptaneis cooled to -25 F. To this mix. ture there is added 15 grams of thecatalyst prepared by dissolving 1 gram of titanium tetrachloride and0.86 gram of trichloroacetic acid in 13.2 grams of carbon tetrachlorideover a period of 30 minutes while maintaining the reaction temperaturebetween 25 and 24" F. The reaction mixture is stirred an additional 3.5hours at this temperature and 250 ml. of methanol is added to remove thecatalyst and precipitate the polymer. The polymer is dissolved inbenzene, re-precipitated in methanol and. dried by heating.Polyisobutene prepared in this manner has a molecular weight of 156 X 10Example 9 ride.

F. To this mixture there is added over a 1%,

6 Exam pie 1 0 The procedure of Example 2 is repeated using a catalystwhich is prepared by dissolving 3.44 grams (0.0208 mole) oftrichloroacetic acid and 0.5 gram (0.0026 mole) of titaniumtetrachloride in 30 grams of carbon tetrachloride.

Example 11 A mixture of 850 grams of isobutene and 150 grams ofpiperylene is cooled to 107" F. by the addition of Dry Ice. To thismixture there is added over a period of A2 hour, 150 grams of thesolution prepared by dissolving 10 grams of titanium tetrachloride and4.3 grams of trichloroacetic acid in 135.7 grams of carbontetrachloride. The reaction temperature is maintained at 107 F.throughout the addition. The reaction mixture becomes very viscous and500 ml. of methanol is added to remove the complex and stop thereaction. The methanol and other unreacted chemicals are decanted and800 ml. of toluene is added carefully and slowly to dissolve thecopolymer. This solution is poured into 2 gallons of methanol toprecipitate the copolymer which is redissolved in 1 liter of benzene andreprecipitated with methanol. The copolymer is dried by heating and hasa molecular weight of 42X 10 Example 12 A mixture of 900 grams ofisobutene, grams of isoprene and 500 grams of n-heptane is cooled to-107 F. by the addition of Dry Ice. To this mixture there is addeddropwise over a period of 1 hour, grams of the catalyst solutionprepared as in Example 9. The reaction temperature is maintained at 107F. throughout the addition and for an additional /2 hour. The reactionis concluded by adding 800 ml. of methanol which decomposes the complexand precipitates the polymer. The precipitate is dissolved in 800 ml. ofbenzene and reprecipitated by pouring into 3 gallons of methanol. Theprecipitated polymer is dissolved in 600 ml. of benzene and 400 grams ofmineral oil is added. The benzene is removed by distillation leaving a50% mineral oil solution of the copolymer of isobutene and isoprenehaving a molecular weight of 50 10 Example 13 A mixture of 150 grams ofisobutene and 150 grams of isoprene is cooled to 107 F., and 45 grams ofa solution prepared by dissolving 3 grams of titanium tetrachloride and1.3 grams of trichloroacetic acid in 40.7 grams of carbon tetrachlorideis added dropwise over a period of 45 minutes. The reaction isexothermic and the reaction temperature reaches 50 F. during theadidtion. Methanol is added to the reaction mixture to precipitate alight yellow rubber.

Example 14 A mixture of 80 grams of isobutene, 20 grams of cisbutene-2,and 200 grams of n-heptane is cooled to 25 hour period, 15 grams of asolution prepared by dissolving 1 gram of titanium tetrachloride and0.43 gram of trichloroacetic acid in 13.57 grams of carbontetrachloride. The reaction temperature is maintained at 25 F. duringthe addition and for an additional period of 4 /2 hours at which time400 ml. of methanol is added to stop the reaction and decompose thecatalyst. The methanol is decanted from the polymer and the polymer isdissolved in warm benzene. The clear solution is poured into methanolwith stirring and after /2 hour, the methanol-benzene mixture is removedfrom the flask leaving the product which is dried by heating. Thepolymer prepared in this manner has a molecular weight of 86 X10 Example15 A mixture of 60 grams of isobutene, 40 grams of cisbutene-2, and 200,grams of n-heptane is cooled to 25 F. To this mixture there is added 15grams of a solution containing the catalyst prepared as in Example 12over a period of 1% hours. The temperature is maintained between 21 and25 F. throughout the addition and for an additional 4 /2 hours at whichtime the reaction is stopped by adding 400 ml. of methanol. The methanolis decanted leaving the polymer residue which is dissolved in warm.benzene. The clear solution is poured into methanol to reprecipitate thepolymer. The methanol is removed and the polymer residue dried byheating. The polymer prepared in this manner has a molecular weight of43 X 10 Example 16 A mixture of 80 grams of isobutene, 20 grams oftransbutene-2 and 200 grams of n-heptane is cooled to 25 F. and 15 gramsof the catalyst solution prepared as in Example 12 is added over aperiod of 70 minutes While maintaining the reaction temperature at 25 F.The reaction mixture was stirred an additional /2 hours at thistemperature and 400 ml. of methanol is then added. The methanol-heptanemixture is removed and the polymer dissolved in 250 grams of benzene.The clear solution is poured into methanol with stirring for /2 hour andthe methanol-benzene mixture is decanted leaving a polymer which isdried by heating and has a molecular weight of 129x10 Example 17 Amixture of 40 grams of isobutene, 60 grams of transbutene-2 and 200grams of n-heptane is cooled to 25 F. and 15 grams of the catalystsolution prepared as in Example 12 is added over a period of 1% hours.The reaction temperature is maintained between -23 and 2S F. throughoutthe addition period and for an additional 4% hours. The reaction isstopped by adding 400 ml. of methanol with stirring. The methanol isdecanted from the precipitate and the precipitate dissolved in 250 gramsof warm benzene. The clear solution is poured into methanol withstirring to precipitate the product. The benzene-methanol mixture isremoved and the precipitate dried by heating. The polymer prepared inthis manner has a molecular Weight of 136x10 Example 18 A mixture of 80grams of isobutene, 20 grams of hutene-l, and 200 grams of n-heptane iscooled to 25 F. and 15 grams of the catalyst solution prepared as inExample 12 is added over a period of 70 minutes. The reactiontemperature is maintained between 22 and -2S F. throughout the additionand for an additional 5 /2 hours. The catalyst is then precipitated byadding 400 ml. of methanol. The methanol-heptane mixture is decanted andthe residue dissolved in 250 grams of warm benzene- The clear solutionis then poured into methanol with stirring to reprecipitate the polymer.After removing the methanol benzene mixture the precipitate is dried byheating. The polymer prepared in this manner has a molecular weight of59X Example 19 A mixture of 60 grams of isobutene, 40 grams of hutene-l,and 200 grams of n-heptane is cooled to 25 F. and grams of the catalystsolution prepared as in Example 12 is added over a period of 70 minutes.The reaction temperature is maintained between 23 and 25" F. throughoutthe addition and for an additional 4 /2 hours at which time the reactionis stoppedby adding 400 ml. of methanol. The methanol-heptane mixture isremoved and the residue dissolved in 250 grams of benzene by heating toreflux for /2 hour. The clear solution is poured into methanol toreprecipitate the polymer. After removing the methanol-benzene mixturethe residue is dried by heating. The polymer prepared in this manner hasa molecular weight of 32 10 8 Example 20 The procedure of Example 2 isrepeated using a catalyst which is prepared as a 10% solution inn-heptane by dissolving 2 grams of titanium tetrabromide and 0.83 gramof tribromoacctic acid in 25.65 grams of n-heptane. No hydrogen bromideis evolved when the catalyst is prepared.

Example 21 The procedure of Example 4 is repeated using the catalystprepared as a 5% solution in n-heptane by dissolving 1 gram of titaniumtetrachloride and 0.77 gram of tribromoacetic acid in 33.6 grams ofn-heptane. No hydrogen halide is formed when the catalyst is prepared.

Example 23 T o 300 grams of isobutene cooled to 30 F. there is addedover a 3-minute period, 5.7 grams of a catalyst solution prepared bydissolving 1 gram of titanium tetrachloride and 0.43 gram oftrichloroacetic acid in 8.57 grams of n-heptane. The reactiontemperature is maintained between 21 and 3 1 F. throughout the additionand for a total reaction time of 1 hour. Ammonia gas (0.051 gram) isbubbled under the surface of the polymer solution to deactivate thecatalyst and the solution is stirred for an additional 15 minutes. Atthis point the solution is divided into two portions, A and B. Portion Ais poured into methanol to. precipitate the polymer which is thendissolved in benzene and reprecipitated with methanol. The polymerisolated in this manner has a molecular weight of 180x10 Portion B isadded to mineral oil and the volatile materials removed by heating. Theresidue is a mineral oil solution of polyisobutene having a molecularweight of 175 X 10 Example 24 A solution of 10 grams of trichloroaceticacid in 66.54 grams of petroleum ether (boiling point range 39-5 l C.)is cooled to 43 F. and 11.57 grams of titanium tetrachloride is addeddropwise. No hydrogen chloride is formed. The mixture is stirred at thistemperature for 1% hours. The petroleum ether is evaporated leaving thetitanium tetrachloride-trichloroacetic acid catalyst as the residuehaving a chlorine content of 65.8% (theory 62.4%) and a titanium contentof 13.5% (theory 15.25%).

Example 25 The procedureof Example 5 is repeated using as catalyst 1.3grams of the solid catalyst prepared as in Example 22.

Example 26 To grams of isobutene there is added a solution containing0.8 gram of titanium tetrachloride and 0.35 gram of trichloroacetic acidin 13.85 grams of n-heptane over a period of 1 hour while maintainingthe reaction temperature at 72 F. to 77 F. The reaction mixture ismaintained within this temperature range and stirred for a total of 3 /2hours. The catalyst is removed by the addi tion of methanol which alsoprecipitates the polymer. The precipitate is dissolved in benzene andthe clear solution is poured into methanol. The precipitate is dried byheating. Polyisobutene prepared in this manner has a molecular Weight of2000.

This invention is not intended to encompass the polymerization processeswhereby a titanium halide is added to a trihaloacetic acid-olefinmixture or whereby a trihaloacetic acid is added to a titaniumhalide-olefin mixture.

9 That the process of the present invention is superior to either ofthese processes is illustrated by the following examples.

Example 27 A mixture of 186 grams of n-heptane, 100 grams (1.8 moles) ofisobutene and 1 gram (0.0052 mole) of titanium tetrachloride is cooledto 25 F. A solution of 0.43 gram (0.0026 mole) of trichloroacetic acidin 14.57 grams of carbon tetrachloride is added dropwise to the cooledisobutene solution over a period of 15 minutes during which time thereaction temperature reached -2 F. The reaction mixture is cooled to 25"F. and stirred for a total of 6.5 hours. Methanol is then added todestroy the catalyst. The methanol layer is removed and the residueWashed once with methanol and dissolved in benzene. The benzene solutionis dissolved in 300 grams of mineral oil and the benzene is removed byheating to 120 C./9 mm. Polyisobutene prepared in this manner has amolecular Weight of 96 X10 Example 28 A mixture of 200 grams ofn-heptane, 100 grams 1.8 moles) of isobutene and 0.43 gram (0.0026 mole)of trichloroacetic acid is cooled to 25 F. To this mixture there isadded 15 grams of a solution prepared by dissolving 1 gram (0.0052 mole)of titanium tetrachloride in 14 grams of carbon tetrachloride over aperiod of 55 min utes. The reaction temperature reaches a maximum of 9F. during and shortly after the addition and is cooled to 23 F. and heldat this temperature for a total reaction time of 6.5 hours. The reactionmixture is then washed with methanol and dissolved in benzene. Thebenzene solution is washed with methanol, dried, and dissolved in 300grams of mineral oil. The benzene is removed by heating, leaving amineral oil solution containing 24% polyisobutene having a molecularweight of 90 X10 The inadequacies of the processes of Examples 27 and 28should be obvious in light of the present invention. In both examples,the reaction temperature is difiicult to control and the molecularweight of the product is low with respect to the process of the presentinvention. Specifically, the temperature rise in Example 27 is 22 F. andthe product has a molecular weight of only 96,000 and in Example 28, thetemperature rise is 16 F. and the molecu lar weight of the polymer isonly 90,000.

The interpolymerization products obtained by the process of thisinvention may be treated with sulfur containing materials such as P 8 toproduce highly cross-linked rubber-like materials which are useful aselectrical wire coatings. For example, heating a mixture of 750 grams ofthe interpolymer of 80% (by weight) of isobutene and 20% of piperyleneand 594 grams of mineral oil to a temperature of 210 C. and adding 91grams of P 8 in small increments over a one-hour period resulted in theformation of a light colored rubber.

The polymers recovered from the process of this inven tion range inmolecular weight from about 5000 to about 400,000. The products of thisinvention are readily soluble in petroleum oils, small amounts greatlyincreasing the viscosity thereof. The preferred starting material,isobutene, produces polymers which not only increase viscosity butlikewise favorably affect the viscosity-tempera ture curve of the oil towhich it is added.

What is claimed is:'

1. In the process of polymerizing an olefin, the steps of preparing ahomogeneous catalyst mixture by mixing a titanium halide selected fromthe class consisting of titanium tetrafluoride, titanium tetrachloride,and titanium tetrabromide with from about 0.1 to about molar proportionsof a trihaloacetic acid selected from the class consisting oftrichloroacetic acid, tribromoacetic acid, and trifluoroacetic acid andthereafter contacting said homogeneous catalyst mixture with an olefinselected from the 10 class consisting of isobutene, mixtures ofisobutene and conjugated dienes, and mixtures of isobutene withl-butene, cis-2-butene, or trans-Z-butene to effect polymerization; withthe proviso that said mixtures can contain minor amounts of C and Chydrocarbons.

2. In the process of polymerizing an olefin, the steps of preparing ahomogeneous catalyst mixture in a liquid solvent selected from the classconsisting of hydrocarbons and halohydrocarbons by dissolving a titaniumhalide selected from the class consisting of titanium tetrafluoride,titanium tetrachloride and titanium tetrabromide and from about 0:10 toabout 10 molar proportion of a trihaloa'cetic acid in said solvent andthereafter contacting said homogeneous catalyst mixture with an olefinselected from the class consisting of isobutene, mixture of isobuteneand conjugated dienes, and mixtures of isobutene with l-butene,cis-2-butene, or trans-Z-butene to effect polymerization; with theproviso that said mixtures can contain minor amounts of C and Chydrocarbons.

3. The process of claim 1 characterized further in that the titaniumhalide is titanium tetrachloride.

4. The process of claim 1 characterized further in that thetrihaloacetic acid is trichloroacetic acid.

5. In the process of polymerizing an olefin selected from the classconsisting of isobutene, mixtures of isobutene and conjugated dienes,and mixtures of isobutene with l-butene, cis-Z-butene, ortrans-Z-butene; with the proviso that said mixtures can contain minoramounts of C and C hydrocarbons, the steps of preparing a homogeneouscatalyst mixture by dissolving titanium tetrachloride and from about 0.1to about 10 molar proportions of trichloroacetic acid in ahalohydrocarbon solvent, the amount of titanium tetrachloride being inthe range of from about 0.01 to about 2% by weight of said olefin andthereafter contacting said homogeneous catalyst mixture with said olefinto effect polymerization.

6. The process of claim 5 characterized further in that the olefin iscommercial grade isobutene.

7. The process of claim 5 characterized further in that the olefin is amixture of isobutene and piperylene in the weight ratio of from about99:1 to about 1:1.

8. The process of claim 5 characterized further in that the homogeneouscatalyst mixture is prepared by mixing titanium tetrachloride with 0.5molar proportion of trichloroacetic acid;

9. In the process of polymerizing commercial grade isobutene, the stepsof preparing a homogeneous catalyst mixture by dissolving titaniumtetrachloride and 0.5 molar proportion of trichloroacetic acid in carbontetrachloride and adding the homogeneous catalyst mixture to theisobutene to effect polymerization.

10. In the process of polymerizing a mixture of parts by Weight ofisobutene and 15 parts by weight of piperyl ene, the steps of preparinga homogeneous catalyst mixture by dissolving titanium tetrachloride and0.5 molar proportion of trichloroacetic acid in carbon tetrachloride andadding the homogeneous catalyst mixture solution to the olefin mixtureto elfect polymerization.

11. The process of polymerizing isobutene containing up to 70% ofl-butene, cis-2-butene, or trans-2-butene comprising the steps ofpreparing a homogeneous catalyst mixture by mixing a titanium halideselected from the class consisting of titanium tetrafiuoride, titaniumtetrachloride and titanium tetrabromide with from about 0.1 to about 10molar proportions of a trihaloacetic acid and thereafter cont-actingsaid homogeneous catalyst mixture with the isobutene mixture to eflFectpolymerization.

References Cited UNITED STATES PATENTS 2,891,595 6/1959 Kuntz et a].26085.3

(Other references on following page) 11 OTHER REFERENCES Ambroz et al.:Jfof Poly. Sci., 30, July 1958, pp. 38L-389.

12 Vesely: J. Poly. Sci., 30, July 1958, pp. 375-380. Plesch: Chem.Soc. 1. (London), 1950, pt. I, pp. 543- Plesch: Chem. Soc. J. (London),1953, pt. 2, pp. 1653- 5 J. L SCHOFER, Primary Examinel Meier: Chem.Soc. J. (London), 1950, pt. IV, pp.

F. L. DENSON, M. B. KURTZMAN,

Assistant Examiners.

1. IN THE PROCESS OF POLYMERIZING ANOLEFIN, THE STEPS OF PREPARING AHOMOGENEOUS CATALYST MIXTURE BY MIXING A TITANIUM HALIDE SELECTED FROMTHE CLASS CONSISTING OF TITANIUM TETRAFLUORIDE, TITANIUM TETRACHLORIDE,AND TITANIUM TETRABROMIDE WITH FROM ABOUT 0.1 TO ABOUT 10 MOLARPROPORTIONS OF A TRIHALOACETIC ACID SELECTED FROM THE CLASS CONSISTINGOF TRICHLOROACETIC ACID, TRIBROMOACETIC ACID, AND TRIFLUOROACETIC ACIDAND THEREAFTER CONTACTING SAID HOMOGENEOUS CATALYST MIXTURE WITH ANOLEFIN SELECTED FROM THE CLASS CONSISTING OF ISOBUTENE, MIXTURES OFISOBUTENE AND CONJUGATED DIENES, AND MIXTURES OF ISOBUTENE WITH1-BUTENE, CIS-2-BUTENE, OR TRANS-2-BUTENE TO EFFECT POLYMERIZATION; WITHTHE PROVISO THAT SAID MIXTURES CAN CONTAIN MINOR AMOUNTS OF C3 AND C5HYDROCARBONS.